Microstructural and microprobe analyses of as-cast and annealed alloys (1,000 degrees C for 61 h) revealed a new congruently melting Hf0.45Ti0.55Ni2 compound in the Hf-Ti-Ni system. The compound forms two-phase equilibria with Hf7Ni10, Hf3Ni7, alpha HfNi3 and TiNi3 and exhibits a homogeneity range of 18-24 at.% Ti at 65 +/- 0.5 at.% Ni. Its crystal structure was determined by single-crystal and powder X-ray diffraction. Hf0.45Ti0.55Ni2 crystallizes in a derivative of the Co1.75Ge prototype exhibiting statistical mixture of hafnium and titanium atoms on 2d site and two 2a, 2c sites occupied by nickel atoms: PS hP6, SG P63/mmc, a = 4.225(2), c = 5.044(4) & Aring;. The Rietveld-refined composition, Hf0.482(2)Ti0.518(2)Ni2, is in close agreement with both the single-crystal X-ray diffraction data and the energy-dispersive X-ray analysis results. The homogeneity range of the compound Hf x Ti1-xNi2 has been refined from powder X-ray diffraction and energy-dispersive X-ray data: (0.55 <= x <= 0.72), variation of the lattice parameters is the following: a = 4.2045(3) - 4.185(1), c = 5.0055(4) - 5.000(1) & Aring;. The microstructure shows a characteristic twin morphology. The microhardness of the compound was measured as 1,160 +/- 20 and 1,140 +/- 60 H mu for single-phase as cast alloys containing 18 and 24 at.% Ti, respectively. Electronic structure calculations based on the LMTO method for the ordered model HfTiNi4 (P6/mmm) indicate a metallic behavior with significant Ti-Ni, Hf-Ni, and Ti-Hf bonding interactions. The analysis of DOS and COHP indicates strong covalent contributions alongside Ni-Ni antibonding states, suggesting a complex hybrid metallic-covalent bonding nature that stabilizes the Hf-Ti-Ni three-dimensional network.

B4C–TiB2 ceramic materials were prepared by spark plasma sintering of powder mixtures B4C+TiB2 (12 wt.%) in an argon atmosphere at 1900°C and a uniaxial pressure of 70 MPa. X-ray powder diffraction was used for the phase analysis and to refine the crystal structures of the individual phases. The influence of homogenization of the initial powders (using ball milling) on the mechanical properties of the ceramics was studied. Vickers hardness values of 38.8 GPa (without ball milling) and 41.1 GPa (ball-milled starting powders) for B4C–TiB2 composites were reached and the relative density of the samples exceeded 99 %.

The new ternary berthollide Zr7Ru6+xGa17-x (0 <= x <= 2.0) has been synthesized by arc melting stoichiometric amounts of the elements. The homogeneity ranges at 870 K of the phases have been examined using powder Xray diffraction and energy-dispersive X-ray analysis. Zr7Ru6Ga17 crystallizes in a new cubic structure-type (Pearson symbol cF120, space group Fm3m no. 225, a = 12.409(1) & Aring;, Z = 4) extending the family of closely-related cubic structures described by the Pearson symbols cF116-120. The crystal structure of Zr7Ru6Ga17 can be regarded as a superstructure polyhedral variant of CaF2. Density-functional electronic structure calculations performed for an ordered structural approximant uncover pronounced features near the Fermi level, including several van Hove singularities (vHSs), indicative of a potential electronic instability. Chemical bonding analysis based on the-COHP method reveals that heteroatomic Zr-Ga and Ru-Ga contacts dominate the bonding landscape, with zirconium showing an unexpectedly strong covalent contribution despite its minority fraction. Complementary physical measurements demonstrate a characteristic type of transport and thermodynamic behavior that is directly influenced by the structural disorder and the peculiar electronic structure. The combination of a new cubic architecture, Fermi-level singularities and unconventional bonding motifs places Zr7Ru6+xGa17-x as a promising platform for exploring structure-property correlations in Ga-rich intermetallics and expands the chemistry of the cF120 family.

Abstract Equiatomic intermetallic compounds composed exclusively of d-block elements remain rare, as competing bonding preferences typically favor phase separation or structural simplification. Here we introduce a previously unexplored class of equiatomic polar intermetallics, LnMnPt (Ln = La, Ce, Nd, Gd, Tm, Y), in which a heavy 5d element acts as a relativistic electronic mediator. Depending on the rare-earth element size, the compounds adopt either the LaNiAl-type (Pnma) or ZrNiAl-type (P6̅2m) structure, both built from polyanionic Mn–Pt frameworks hosting geometrically distinct rare-earth sublattices. Magnetic measurements reveal a chemically enforced separation into two interacting magnetic subsystems: a robust Mn-derived antiferromagnetic framework and a tunable rare-earth sublattice, giving rise to competing exchange interactions and multiple magnetic transitions. Fully relativistic density functional theory calculations identify Pt as a spin–orbit-active yet magnetically inert center that governs both bonding and magnetocrystalline anisotropy. The large magnetocrystalline anisotropy originates primarily from spin–orbit coupling associated with Pt 5d states, as supported by comparison with hypothetical Pd analogues, while rare-earth–Mn–Pt exchange interactions tune the easy-axis direction and exchange balance. These results establish LnMnPt as a model system in which relativistic effects are harnessed to decouple and tune magnetic interactions within a fixed structural framework. More broadly, this work demonstrates that heavy 5d elements can function as relativistic control centers, enabling the design of complex magnetic behavior in polar intermetallics through targeted manipulation of spin–orbit coupling and chemical bonding.

A series of RE 11Rh4In9 intermetallics (RE = Gd, Tb, Ho, and Tm) adopting the Nd11Pd4In9-type structure (space group Cmmm, oS48) was synthesized. The structure of these compounds has been visualized and described through CsCl- and AlB2-type fragment tiling, with the help of in-house developed software, revealing the structure as an intermediate in the CsCl- to AlB2-type structure transformation with 18% of the AlB2-type fragments and no face sharing between these fragments. Magnetic properties of RE 11Rh4In9 (RE = Gd, Tb) have been examined. The compounds undergo transition from para- to ferromagnetic order near 80 K with additional magnetic transitions detectable at lower temperatures. Magnetic entropy change reaches 5.32 and 3.66 J & centerdot;kg-1 & centerdot;K-1 under a magnetic flux density change of mu 0 Delta H = 0-9 T for RE = Gd and Tb, respectively. Relative cooling power and refrigerant capacity are equal to 615.4 and 501.1 J & centerdot;kg-1 in Gd11Rh4In9 and 393.2 and 311.4 J & centerdot;kg-1 in Tb11Rh4In9 under mu 0 Delta H = 0-9 T. RE 11Rh4In9 establishes a structural family of Rh-containing rare-earth intermetallics that exhibit competitive magnetocaloric performance in a broad range with the maximum near 80 K. Subtle changes in the electronic structure govern exchange interactions and magnetic entropy for tuning magnetocaloric properties through controlled f-d hybridizations.

The crystal structure of the phosphide Ta 0.88(1) Fe 1.12(1) P has been determined from X-ray powder diffraction data: full-profile refinement, orthorhombic space group Pnma , a = 6.1036(2) Å, b = 3.5774(1) Å, c = 6.9742(2) Å, R I = 0.042. Examination of the X-ray emission spectra (XES) has revealed that the main maximum of the FeLα band coincides with the high-energy feature of the P L II,III bands, indicating strong hybridization of P s and Fe d electrons. High intensity of the FeKβ″ satellite has been observed and explained. Two components appear in the 57 Fe Mössbauer spectruma measured at temperatures in the range 80–300 K, Fe1 (77(2)%) and Fe2 (23(2)%). The paramagnetic component reflects Fe in the crystallographic position 4 c . The moderate value of the quadrupole splitting of 0.3758 mm s −1 indicates a slight anisotropy of the electric field created by Fe1 in its nearest environment. The second component (Fe2) is attributed to Fe atoms statistically substituting Ta atoms in the crystal structure. Its broader linewidth and distinct isomer shift support this assignment. The relative intensities and hyperfine parameters remain constant with temperature, indicating two thermally stable Fe environments. Results of ab initio calculations carried out using the fully relativistic spin-polarized linear muffin-tin orbital method show good agreement with the experimental data.

A new ternary rare-earth indide, ErCo2In, was synthesized by arc-melting and subsequent annealing at 1070 K for 720 h. The compound extends the RECo2In (RE = Y, Pr, Nd, Sm, Gd, Tb, Dy, Ho) series. Single-crystal X-ray diffraction revealed ErCo2In to crystallize in the TbCo2In-type (a coloring variant of the PrCo2Ga-type) structure type in oP8, space group Pmma, Wyckoff sequence f2ea, a = 4.999(4), b = 4.029(3) and c = 7.078(5) Å. The crystal structure characterization with X-ray methods was further supplemented with DFT and materials informatics methods. The crystal bond analyzer (CBA) was developed as a user-prompt materials informatics software for high-throughput system analysis. CBA allows visual exploration of bonding in binary and ternary systems, and it reveals for ErCo2In the prevalence of the RE-Co interactions in RE–Co–In systems with the mid-range-rare-earth metals (up to Er), while the RE–Co–In systems with RE beyond Er have the prevalence of Co-In interactions.

More than 100 solid-state compounds of the formula RTX2 (R = rare earth metal or Ca, Sr, Ba, T = Group 7-11 3d, 4d, and 5d transition metal, X = Si, Ge, Sn) are known. Most of them adopt the CeNiSi2 or the related LaMnSi2 structure. These two structural types are related, in containing square TX nets and polyacetylene-like X chains, but with a different disposition of the TX units in their nets. Using density functional computational tools, we have investigated the electronic origin of the site preference by the transition metal T and the main group atom X in these two crystal structures. Due to the larger band dispersion of the atomic orbitals at sites with closer neighbors and the stronger bonding feature in the lower half of the energy bands arising, and antibonding features of the upper half of the energy bands, the LaMnSi2 type is preferred for low d electron count, and the CeNiSi2 type for high d electron count. More generally, variation in dispersion (inherently greater in lattice sites with more nearby overlapping atoms) interacts with electron occupation, to explain structural preferences in these and other ternary compounds.

Phase equilibria and the crystal structure of the compounds of the ternary system Y–Ni–As were studied using X-ray phase and structural analyses, and the phase diagram was constructed at 970 K in the range of 0–0.67 mol. % As. Samples for investigation were prepared by sintering of the pressed pellets of the mixtures of the pure components in evacuated silica tubes at 970 K for 240 h, and then were arc-melted under purified argon atmosphere. The as-cast samples were again sealed in a silica tubes, and then heat treated at 970 K during 1500 h. Annealed alloys were quenched in cold water without breaking the ampoules. The X-ray powder diffraction data were collected on a powder diffractometers DRON-3M (CuKα-radiation), and Image Plate Huber G 670 (CuK1- radiation). All calculations were performed using WinCSD and FullProf software. The existence of six ternary compounds was confirmed: YNi4As2 (ZrFe4Si2 type), Y2Ni12As7 (Zr2Fe12P7 type), Y6Ni20.04As12.78 (Y6Ni20.04As12.78 type), Y6Ni15As10 (Tb6Ni15As10 type), Y20Ni42As31 (Sm20Ni42P31 type), and YNiAs (LiBaSi type). Moreover, the crystal structures of two ternary arsenides were refined for the first time using the X-ray powder diffraction data: Y2Ni12As7, Zr2Fe12P7 type structure, space group P-6, lattice parameters a = 9.3582(2) Å, c = 3.8149(1) Å, final residual values are RB = 0.078, RP = 0.084; and Y6Ni15As10, Tb6Ni15As10 type structure, space group P63/m, a = 17.0101(1) Å, c = 3.88759(4) Å, RB = 0.053, RP = 0.106. For the last arsenide, the splitting of the positions of arsenic atoms As1 and As2 on the 63-axis is observed, and, as a result, neighboring nickel atoms also occupy split positions. For split positions Ni2/Ni3/Ni4, the total occupancy is about 100%. As a consequence, it has been confirmed that the refined composition of this arsenide coincides with the previously known formula Y6Ni15As10. The crystal structures of ternary arsenides Y2Ni12As7 and Y6Ni15As10 belong to a homologous series of flat bilayer hexagonal structures with a metal:metalloid ratio of 2:1, whose composition is described by the formula Lnn(n-1)M(n+1) (n+2)Xn(n+1)+1.

Hf7Pd7Ga3 has been obtained by arc melting the elements under argon atmosphere. The crystal structure of the new compound has been determined from single-crystal X-ray diffraction data, while powder X-ray diffraction has been applied for the characterization of polycrystalline samples. Hf7Pd7Ga3 (oS68, Cmce, a = 12.948(4), b = 9.585(3), c = 9.581(3) & Aring;, Z = 4) crystallizes with a ternary version of the Zr7Ni10 type of structure exhibiting a statistical mixture of palladium and gallium atoms on three crystallographically independent nickel sites. The crystal structure of Hf7Pd7Ga3 features a Pd-Ga framework built of sinusoidal layers of Pd and Ga, which stack along the b axis sandwiching the Hf atoms. Density functional theory calculations for Hf7Pd7Ga3 in an idealized, ordered structure and, for comparison, hypothetical Hf7Pd10 reveal that partial substitution of Pd by Ga helps to alleviate the strong Pd-Pd antibonding interactions observed in Ga-free Hf7Pd10.

The interfacial resistance between a current collector and an active material of a supercapacitor leads to energy losses and a decrease in the specific power of the device. In addition, low adhesion of the active material to the collector can cause degradation of the supercapacitor during operation. In this study, we propose a method to reduce the interfacial resistance at the interface between a current collector and active material by forming laser-induced periodic surface structures (LIPSS). We show that laser structuring in inert gas (N2) environment results in improvement of electrochemical characteristics of supercapacitors. The charge-transfer resistance determined by the voltage drop during the cell discharge after femtosecond laser processing of the collectors decreases by 90% compared to the untreated collectors. The main effects of improving the electrochemical characteristics can be understood by an increase in the contact area between the electrode material and the collector due to the formation of LIPSS, which reduces the specific resistance. Laser structuring also causes certain chemical changes on the surface of the current collector, which can contribute to improving the electrical conductivity and the chemical stability of the contact. The LIPSS on the surface improves the adhesion of the active material to the current collector, which reduces the risk of mechanical delamination during the cyclic charge-discharge processes. A significant reduction in internal resistance with nanostructured electrodes opens promising avenues for increasing the specific power of supercapacitors of various types. The laser processing method does not require the use of additional reagents or multicomponent sublayers, which simplifies the approach and makes it attractive for application requiring scale up.

For the first time, the complete single-crystal structure study of the compound Y1-xYbxFe2Si2 x=0.24 was performed. It belongs to the CeGa2Al2 structure type, Pearson’s symbol tI10,139, space group I4/mmm, lattice parameters a = 3.911(1), c = 9.929(4) Å, Z = 2. The compound was prepared by arc-melting of the initial elements with а purity of not less than 99.9 % under argon followed by annealing in silica tubes at 870 K for 1400 h. Single crystals for structural examination were selected under a microscope from the broken alloys obtained. X-ray diffraction data of one of the irregularly faceted single crystals was obtained at a temperature of 300(2) K using a single crystal X-ray diffractometer Bruker D8 Venture with monochromatized MoKα-radiation. The structure is refined using the program SHELXL, version 2018/3 (full-matrix least-squares refinement with anisotropic atomic parameters), R1 = 0.015, wR2 = 0.036 for 107 unique reflections with Io > 2σ(Io) and 10 refined parameters. Coordinates of atoms are the following: 2R at 2а 0 0 0; 4Fe at 4d 0 1/2 1/4; 4Si at 4e 0 0 z, z=0.3760(1), R = 0.767(5)Y + 0.233(5)Yb. The coordination numbers of R, Fe, and Si atoms are 20, 12, and 10, respectively. The interatomic distances, except Fe–Si, are longer than the sum of the metallic radii of the corresponding atoms. Fe–Si distances (2.322(1) Å) are smaller than the sum of the radii of these atoms (2.43 Å) and indicate a significant interaction between Fe and Si in the structure. Currently known RFe2Si2 (R=Y, Yb) are members of complete series of compounds RFe2Si2 (R=rare earths) isotypic with CeGa2Al2. A partial substitution Y by Yb does not change the crystal structure as well a cell volume of Y1-xYbxFe2Si2 x=0.24.

New ternary rare-earth indides RE23Co6.7In20.3 (RE = Gd-Tm, Lu) have been synthesized by arc-melting the elements under argon and subsequent annealing at 870 K for 1200 h. Single-crystal X-ray diffraction revealed Er23Co6.7In20.3 to crystallize in a new structure type in oP100, space group Pbam and Wyckoff sequence h11g13da with a = 23.203(5), b = 28.399(5), c = 3.5306(6) angstrom. The crystal structures of RE23Co6.7In20.3 (RE = Tb, Ho, Er and Tm) were determined from single crystal and powder X-ray diffraction data and further investigated by DFT methods. The compounds belong to a large family of ternary rare-earth indides with intergrowth of the AlB2- and CsCl-type related slabs. In the Er23Co6.7In20.3 structure, four types of fragments REIn and RET of CsCl-type, as well as RET2 and REIn2 of AlB2-type, are present simultaneously. A simple Python tool was developed to determine the coordination number for each crystallographic site with various methods and tested on the complex structure of RE23Co6.7In20.3.

The new ternary compound Zr7Pd7-xGa3+x (0 <= x <= 1.8) was synthesized by arc melting the elements under argon and subsequent annealing the ingots at 870 K for 720 h. The polycrystalline samples were characterized by powder X-ray diffraction (XRD) and the crystal structure of the compound was determined from single crystal X-ray diffraction data. Zr7Pd7Ga3 crystallizes with a ternary version of the Zr7Ni10 type of structure exhibiting statistical mixtures of palladium and gallium atoms on three crystallographically independent nickel sites (oS68, Cmce, a = 12.997(3), b = 9.623(2), c = 9.630(2) angstrom, Z = 4, R1 = 0.033, wR2 = 0.067 for 719 unique reflections with I-o > 2 sigma(I-o) and 48 refined parameters). The crystal structure of Zr7Pd7Ga3 is represented by a 3D Pd-Ga framework built of sinusoidal layers of Pd and Ga stacking along the b axis sandwiching the Zr atoms. The homogeneity range of the compound Zr7Pd7-xGa3+x has been refined from powder XRD and EDX data: 0 <= x <= 1.8; variation of the lattice parameters is the following: a = 13.0174(8)-12.904(3), b = 9.6306(8)-9.559(8), c = 9.6348(8)-9.700(5) angstrom. Electronic structure calculations have been performed for an idealized model Zr7Pd10 as well as a model compound Zr7Pd6.5Ga3.5 revealing that the Ga-free Zr7Pd10 is significantly destabilized by strong Pd-Pd anti-bonding interactions. Substitution of Pd by Ga reduces those, stabilizing Zr-7(Pd,Ga)(10) which features strong heteroatomic bonding between Zr and the Pd/Ga substructure, putting it into the class of polar intermetallics.

The crystal structure of the ternary phosphide Ce2Ni12P5 (La2Ni12P5-type structure) has been determined from X-ray powder diffraction data: full profile refinement, monoclinic symmetry, space group P2(1)/m, a = 10.7809(2) angstrom, b = 3.6869(1) angstrom, c = 13.1490(3) angstrom, beta = 107.776(4)degrees, R-I = 0.068, R-P = 0.044, R-wP = 0.060. Ce2Ni12P5 is a ferromagnet with a Curie temperature of 5.8(5) K. A significant deviation from the linearity of the temperature dependence of the electrical resistance for Ce2Ni12P5 has been found. The low-temperature part of the electrical resistance indicates the presence of magnetic interactions in Ce2Ni12P5. The influence of a magnetic field on the electrical resistance of Ce2Ni12P5 has been studied. The X-ray absorption spectrum at the Ce L-III edge and X-ray emission spectra of Ni and P at the K and L-III edges have been studied experimentally and theoretically using DFT+U calculations. The calculations show good agreement with the experimental measurements. The effective valence of Ce in Ce2Ni12P5 determined based on the Ce L-III absorption spectrum is theta(eff) similar to 3.05.

Pseudo-ternary solid solutions, Lu(Ni1-xCox)C2 (0≤ x ≤1), were studied by means of powder X-ray diffraction, differential thermal analysis as well as electrical resistivity and heat capacity measurements. The crystal structure of the Lu(Ni1-xCox)C2 series, as investigated by means of X-ray powder diffraction, is structure type CeNiC2, space group Amm2, Pearson symbol oS8. The structural analysis reveals a non-monotonous evolution, in particular for the a- and c-lattice parameters, resulting in a non-linear decrease of the unit cell volume, markedly deviating from Vegard’s rule, due to non-isoelectronic substitution of Ni by Co. Utilizing differential thermal analysis (DTA) data, a pseudo-binary phase diagram LuNiC2–LuCoC2 has been constructed. The evolution of charge density wave order in Lu(Ni1-xCox)C2, which reaches an ordering temperature TCDW ≅ 450K for LuNiC2, was studied by means of electrical resistivity and heat capacity measurements. For solid solutions prepared via the floating-zone melting technique it became feasible to trace charge density wave (CDW) features of the temperature dependent electrical resistivity, thus, indicating a critical composition for the suppression of CDW order in Lu(Ni1-xCox)C2 at around x ≈ 0.15 – 0.17, which matches with a distinct drop of the composition dependent electronic Sommerfeld coefficient of the low temperature heat capacity of Ni-rich solid solutions.

Ternary carbides R2Ni5C3 (R = La-Nd, Sm, Gd, Tb) are the only representatives of the family of interstitial carbides (i.e., compounds with the composition RxTyCz, where T is a transition metal and 2 <= (x + y)/z <= 4). The crystal structures (space group P4/mbm) of Sm2Ni5C3 [a = 8.26131(7) angstrom, c = 3.89090(4) angstrom, RB = 3.2 %, Rp = 1.3 %] and Gd2Ni5C3 [a = 8.24683(4) angstrom, c = 3.85398(2) angstrom, RB = 3.9 %, Rp = 3.6 %] are refined for the first time. They are considered to be built by distorted [R8]-cubes incorporating [CNi6]-octahedra condensed with [C2R8]-trigonal bi-prisms. The structural units are characteristic of the CaTiO3- and AlB2-prototypes, respectively. Temperature dependencies of the magnetic susceptibility, specific heat, electrical resistivity, thermal conduc-tivity, and thermopower in the range 1.8 K (2 K) - 300 K are studied. R2Ni5C3 with R = Nd, Sm, Gd, order antiferromagnetically at TN = 3.4, 6.6, and 22.2 K, respectively. The nature of magnetic transitions in Ce2Ni5C3 at Tmag = 2.3 K and Tb2Ni5C3 at 29.4 K requires further clarification. No magnetic orderings for La2Ni5C3 (Pauli paramagnetic) and Pr2Ni5C3 (Curie-Weiss/van Vleck paramagnetic) are detected. Relatively high electrical resistivities and thermal conductivities, together with the small absolute values of Seebeck coefficients, result in poor thermoelectric performance of the R2Ni5C3 carbides. The calculated electronic structure for La2Ni5C3 indicated a rather low density of states at the Fermi level as well as its extreme sensitivity to any doping. The stabilization of the R2Ni5C3 interstitial carbides up to R = Tb is discussed assuming the rigid-band approach as well as the analysis of selected Ni-C interatomic distances.